1. Field of the Invention
The present invention relates to a broadcast address server, and more particularly, to a broadcast address server deployed on a network to transfer packets to all relevant terminals on the network.
2. Description of the Related Art
The implementation of classical layer-3 protocols, including the Internet Protocol (IP), in an Asynchronous Transfer Mode (ATM) network environment has been at the forefront of discussion in the Internet Engineering Task Force (IETF) as well as in the ATM Forum. More specifically, the Next Hop Resolution Protocol (NHRP) and the Classical IP over ATM protocol are proposed as important enabling technologies in this field, which make it possible to deliver IP packets to intended destinations over a connection-oriented ATM network.
In such an ATM-based IP network system, there must be at least one address server to provide address resolution services. Each terminal station sets up a connection to the address server, when powered up, and performs a registration procedure to have its protocol address (IP address) and physical address (ATM address) registered to the address server. The address server has an address translation table to store such IP-ATM address pairs of all relevant terminal stations for later use.
When one terminal station wishes to communicate with another terminal station, the source station first sends an address request to the address server to obtain the physical address corresponding to the protocol address a of the destination station. With the obtained physical address, the source station now establishes an ATM connection to the destination, and then starts a communication session through the established ATM connection. The ATM network environments, however, have no special physical address definitions for the purpose of packet broadcasting. Therefore, the address server cannot translate a given broadcast protocol address to any physical address, meaning that some other mechanism is required to make broadcast communication possible.
To solve the above problem in conventional Classical IP over ATM environments, a broadcast server is deployed on the network to support packet relaying services. That is, the broadcast server forwards each incoming broadcast packet toward all terminal stations on the network. To handle those broadcast packets, the broadcast server has an appropriate protocol stack. Every received packet is examined at the protocol layer as to whether the packet is a broadcast packet having a broadcast destination IP address, before distributing it to the terminal stations.
However, the above-described conventional broadcast server has a problem in the time required for packet transfer, because each received packet should be tested not at the physical later, but at the protocol layer. This higher layer process is much more time-consuming, compared to the physical layer process. Another problem with the conventional system is that the broadcast server can be overloaded because all broadcast packets are concentrated on a single server.
Taking the above into consideration, an object of the present invention is to provide a broadcast address server which can be implemented as an upgraded version of an existing address server to make it possible to distribute broadcast packets in a reduced time period, and with a smaller processing load.
To accomplish the above object, according to the present invention, there is provided a broadcast address server deployed on a network to transmit packets to a plurality of terminals associated therewith. This broadcast address server comprises the following elements: (a) a connection set-up unit which establishes a broadcast connection to the terminals on the network, based on addressing information that is maintained in the broadcast address server; (b) an address response unit which responds to an address resolution request from a source terminal that needs a physical address corresponding to a broadcast protocol address by returning to the source terminal a dedicated broadcast physical address that is used to receive broadcast packets; and (c) a packet transmission unit which receives a broadcast packet that the source terminal has transmitted toward the dedicated broadcast physical address and forwards the received broadcast packet to the terminals on the network.
The above and other objects, features and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate preferred embodiments of the present invention by way of example.